1. Technical Field
The present invention relates generally to the field of above-ground enclosures that protect and provide access to electrical devices, cable terminals and the like. More particularly, the invention relates to such enclosures that are pedestal style housings mounted onto an anchor post and that incorporate lightning protection means, and even more particularly to such enclosures that encase shunts or tunable joint couplers (TJC) used in railroad track operations.
2. Description of the Related Art
Numerous constructions for above-ground enclosures that protect and provide easy access to electrical devices, cable terminals, etc., are well known. The enclosures are constructed of sturdy and durable material such as metal or hard plastic and are often provided with locking means. Examples of various pedestal-type enclosures used for these purposes can be found in U.S. Pat. Nos. 2,916,539, 3,033,912, 3,153,116, 3,162,718, 3,180,920, 3,309,456, 3,404,212, 3,435,124, 3,480,721, 3,652,779, 3,868,474, and 4,852,834.
In the railroad industry it is necessary to provide means to detect the presence of a train at certain locations, such as crossings. To accomplish this, shunts or tunable joint couplers (TJC) are positioned between or adjacent the railroad track, with wiring running from the tracks to the shunt or TJC. As utilized herein a xe2x80x9cshuntxe2x80x9d refers to a component of a loop shunt system that shunts (i.e. terminates the range of) a railroad track signal, while a TJC refers to a component of a railroad track signal loop system that extends the range of a railroad track signal. Characteristic of both a shunt and a TJC is that both receive a railroad track signal utilized to determine the location of a train in proximity to a railroad crossing or junction.
Shunts and TJCs are often buried between railroad tracks for protection. With a buried shunt or TJC, it is more difficult to access the device for repair or replacement, and the device is more susceptible to damage from physical or environmental events. An alternative means to protect the shunt or TJC is to provide a box-type housing set onto a concrete slab or concrete post adjacent the tracks. This provides easier access to the device, but requires the labor-intensive steps of forming a concrete slab or burying a concrete post. In addition, the relative permanence of such concrete limits the relocatability of shunts and TJC devices.
It can therefore be appreciated that a need exists for an improved pedestal enclosure utilized to encase and protect a railroad shunt or TJC which is easily installed adjacent the railroad track at the desired location. The present invention addresses such a need.
The invention is in general an above-ground track signal terminal apparatus located adjacent a railroad track and including a pedestal-style enclosure for protection of a railroad shunt or TJC. The enclosure is lockable, easily erected, provides easy access to the shunt or TJC device, protects the device from physical or environmental damage, including lightning strikes, and preferably provides information identifying the particular crossing to which the shunt or TJC is associated.
The invention comprises in general an anchor post to be driven into the ground, a mounting post connected to the anchor post, a terminal board for connection of electrical wires or cables mounted onto the mounting post, lightning protection means, a suspended, grounded, cable shield surrounding the wires leading to the railroad track, and a removable non-conductive housing to enclose the components, including the shunt or TJC.
The mounting post is connectable to the anchor post at various locations to enable the height to be adjusted. The cable shield surrounding the wires leading to the track is contained within and protected by the removable enclosure housing and is grounded to the mounting and anchor post combination. The shunt or TJC is mounted onto the mounting post using plastic ties or similar non-conductive fastening means so as to maintain electrical isolation from the mounting and anchor post combination. Locking means are provided to secure the housing to the mounting post.